In recent years, there are image forming apparatuses such as a multi-function peripheral (hereinafter, referred to as an “MFP”) and a printer. The image forming apparatus includes a fixing device. The fixing device heats a conductive layer of a fixing belt by using an electromagnetic induction heating method (hereinafter, referred to as an “IH” method). The fixing device fixes a toner image to a recording medium with heat of the fixing belt. An auxiliary heat generation section concentrates magnetic flux during electromagnetic induction heating so as to increase an amount of generated heat in the fixing belt. The auxiliary heat generation section is formed of a magnetic shunt alloy. Magnetic characteristics of the magnetic shunt alloy change depending on a temperature. The magnetic shunt alloy transitions from a ferromagnet to a paramagnet with the Curie point as a boundary. The magnetic shunt alloy generates heat by itself. If the magnetic shunt alloy generates heat by itself, an internal temperature of the fixing belt increases. If the internal temperature of the fixing belt increases, a thermostat of the fixing belt may cause operation errors.